Flavonoids,which are a diverse class of phytonutrients,are used by organisms to respond to nearly all abiotic stresses and are beneficial for human health.Glycosyltransferase,used during the last step of flavonoid bio...Flavonoids,which are a diverse class of phytonutrients,are used by organisms to respond to nearly all abiotic stresses and are beneficial for human health.Glycosyltransferase,used during the last step of flavonoid biosynthesis,is important in flavonoid enrichment.However,little is known about glycosyltransferase in the orchid Dendrobium catenatum(D.officinale).In this study,we isolated a novel C-glycosyltransferase(designated DcaCGT)from the orchid D.catenatum by identifying and analyzing 82 putative genes in the GT1 family.DcaCGT could specifically catalyze not only di-C-glycosylation but also O-glycosylation.Apart from the normal function of catalyzing 2-hydroxynaringenin and phloretin to the respective di-C-glycosides,DcaCGT also catalyzes apigenin to cosmosiin.Targeted metabolic profiling of the substrates(2-hydroxynaringenin,phloretin,and apigenin)and products(vitexin,isovitexin,vicenin-2,nothofagin,3’,5’-di-C-glucosylphloretin,and cosmosiin)in different tissues showed that vicenin-2 was the most abundant product of this novel enzyme.Cosmosiin was detected in flowers and flower buds.We also established that DcaCGT functions expanded throughout the evolution of D.catenatum.Residual OGT activity may help D.catenatum resist drought stress.Our study illustrates the function,origin,and differentiation of DcaCGT and provides insights into glycosylation and molecular propagation processes,which can be used to improve the production of flavonoids by the cultivated medicinal plant D.catenatum.展开更多
基金supported by the 2018 Shaoguan City Science and Technology Plan Project:Special Project of Industry-University-Research Cooperation(no.2018CS11919)2019 Guangdong Province Special Fund for Science and Technology(‘Big project+task list’)Project:Ecological Cultivation and Sustainable Utilization of Danxia Dendrobium officinale,a rare Southern Medicine in Guangdong Province(no.2019gdskjzxzj-zt3-2)+2 种基金Fundamental Research Project of Shenzhen,China(JCYJ20170817105300166)National Key Research and Development Program of China(no.2018YFD1000401)Key Laboratory of National Forestry and Grassland Administration for Orchid Conservation and Utilization Construction Funds(nos.115/118990050,115/KJG18016A)awarded to Z.-J.L.
文摘Flavonoids,which are a diverse class of phytonutrients,are used by organisms to respond to nearly all abiotic stresses and are beneficial for human health.Glycosyltransferase,used during the last step of flavonoid biosynthesis,is important in flavonoid enrichment.However,little is known about glycosyltransferase in the orchid Dendrobium catenatum(D.officinale).In this study,we isolated a novel C-glycosyltransferase(designated DcaCGT)from the orchid D.catenatum by identifying and analyzing 82 putative genes in the GT1 family.DcaCGT could specifically catalyze not only di-C-glycosylation but also O-glycosylation.Apart from the normal function of catalyzing 2-hydroxynaringenin and phloretin to the respective di-C-glycosides,DcaCGT also catalyzes apigenin to cosmosiin.Targeted metabolic profiling of the substrates(2-hydroxynaringenin,phloretin,and apigenin)and products(vitexin,isovitexin,vicenin-2,nothofagin,3’,5’-di-C-glucosylphloretin,and cosmosiin)in different tissues showed that vicenin-2 was the most abundant product of this novel enzyme.Cosmosiin was detected in flowers and flower buds.We also established that DcaCGT functions expanded throughout the evolution of D.catenatum.Residual OGT activity may help D.catenatum resist drought stress.Our study illustrates the function,origin,and differentiation of DcaCGT and provides insights into glycosylation and molecular propagation processes,which can be used to improve the production of flavonoids by the cultivated medicinal plant D.catenatum.
